Digital cable extension transducer

Abstract

The present invention provides a digital cable extension transducer, which is an integral structure of a spool, a spiral spring, a cable guide assembly and a magnet-detecting element for directly sending out a digital signal of a displacement of the monitored object. A circuit board is mounted on a bottom plate of the housing for further data transmission. With the pulleys in the cable guide assembly, the cable extends and winds orderly around the spool. A baffle is provided for shielding both the spool and three pulleys of the cable guide assembly, thereby, to prevent the extended cable derailing from the pulleys when the extended cable releases at high acceleration or loosens by accident.

What is claimed is:  
     
       1. A digital cable extension transducer, comprising: 
       a housing, comprising a side plate for screwing with a base plate, a bottom plate mounted with a circuit board, a hole for a bushing provided in the bottom plate, and a cover for a front edge of the housing;  
       a spool, mounted on a shaft at the center of the base plate, said shaft comprising a catch, said spool comprising an outer flange and an inner flange, said inner flange having a plurality of magnets equally spaced thereon, the inner flange having a socket with a bearing therein, and a spiral spring being mounted between the inner flange and the catch of the shaft;  
       three pulleys mounted on three individual cylinders surrounding the spool on the base plate to constitute a cable guide assembly, wherein the cable guide assembly guides the cable along grooves in the pulleys and assures orderly winding of the cable on the spool at an exact position to measure the displacement of an object to be monitored attached to the cable; and  
       a baffle, being an L-shaped plate to provide for shielding both the spool and said three pulleys, and integrally affixed to the base plate, said baffle comprising a front edge for fixing to said three individual cylinders by respective apertures therein, wherein the distance between an inner wall of the baffle and outer walls of the pulleys is smaller than the diameter of the cable, thereby, to prevent the extended cable from derailing from the pulleys when releasing at high acceleration or loosening by accident.  
     
     
       2. A digital cable extension transducer according to claim  1 , wherein the housing further comprises a frame slot undercut on its outer wall to be fixed on a detecting platform by a frame plate. 
     
     
       3. A digital cable extension transducer according to claim  1 , wherein the base plate further comprises a magnet-detecting element sensing alternative pulse signals subject to displacement of the magnets and dependent on the actual displacement of the monitored object and transmitted in a digital signal to the circuit board. 
     
     
       4. A digital cable extension transducer according to claim  3 , wherein the magnet-detecting element is composed of reed switches.